Electrolyte disturbances after bowel preparation for colonoscopy: Systematic review and meta-analysis.

BACKGROUND AND STUDY AIMS: We conducted a systematic review and meta-analysis of population-based studies to explore pooled prevalence and magnitude of electrolyte changes after bowel preparation for colonoscopy based on the most recent guidelines. PATIENTS AND METHODS: PubMed and Cochrane were queried for population-based studies examining changes in electrolyte values after bowel preparation, published by July 1, 2021. We report prevalences of serum hypokalemia, hyponatremia, hyperphosphatemia, and hypocalcemia after bowel preparation and changes in mean electrolyte values after vs. before bowel preparation using sodium phosphate (NaP) and polyethylene glycol (PEG). RESULTS: Thirteen studies met the inclusion criteria; 2386 unique patients were included. Overall, hypokalemia was found in 17.2% (95% CI 6.7, 30.9) in the NaP group vs. 4.8% (95% CI 0.27, 13.02) in the PEG group. The magnitude of potassium decrease after NaP bowel preparation was significantly increased compared to PEG (mean difference -0.38; 95% CI -0.49 to -0.27, P < 0.001). No study reported on major complications. CONCLUSIONS: Hypokalemia was found in 17.2% of patients after bowel preparation with NaP and in 4.8% of patients with PEG, a finding that is clinically relevant with respect to choosing the type of bowel preparation. The magnitude of the potassium decrease after NaP was significantly higher compared to PEG. These data provide the evidence that supports the recommendation of the European Society of Gastrointestinal Endoscopy against routine use of NaP for bowel preparation.

Safety of low-volume PEG-asc bowel cleansing preparation for colonoscopy: identifying patients at risk for hypokalemia in a prospective cohort study.

Background and study aims The aim of bowel cleansing preparation should be high-quality results and conformance with safety standards. Previously, we reported that hypokalemia occurred in 23.6 % of patients after bowel preparation in a high-risk population on diuretics or hospitalized and referred for colonoscopy. Here we report on a prospective study in a non-selected colonoscopy cohort to identify patients at risk of developing hypokalemia before and after bowel cleansing with low-volume polyethylene glycol with ascorbic acid (PEG-asc). Patients and methods From January 1 to July 31, 2016, we included all patients undergoing colonoscopy in our institution. Prevalences of hypokalemia before and after PEG-asc bowel cleansing for colonoscopy were calculated and risk factors for developing hypokalemia after PEG-asc bowel cleansing were identified. Results In total, 2011 patients were included in the analysis. Of these, 0.8 % had hypokalemia before bowel cleansing with PEG-asc. After bowel preparation, 5.4 % developed hypokalemia. Of the patients, 281 were considered to have "high cardiac risk." The combination of "high cardiac risk" and hypokalemia was present in 1 % of the initial colonoscopy population. Female sex, colorectal cancer diagnosis, and thiazide use were found to be significant predictors for hypokalemia after use of PEG-asc. No arrhythmias or serious adverse events due to hypokalemia occurred. Conclusions Physicians referring patients for colonoscopy should be aware that "high cardiac risk" patients and those on thiazide diuretics undergoing bowel cleansing for colonoscopy are a risk of developing post-cleansing hypokalemia but it remains to be determined whether their risk of developing life-threatening arrhythmias is truly increased.